Question: Express your answer as a mixed number simplified to lowest terms. $13\dfrac{10}{12}-8\dfrac{8}{9} = {?}$
Answer: Simplify each fraction. $= {13\dfrac{5}{6}} - {8\dfrac{8}{9}}$ Find a common denominator for the fractions: $= {13\dfrac{15}{18}}-{8\dfrac{16}{18}}$ Convert ${13\dfrac{15}{18}}$ to ${12 + \dfrac{18}{18} + \dfrac{15}{18}}$ So the problem becomes: ${12\dfrac{33}{18}}-{8\dfrac{16}{18}}$ Separate the whole numbers from the fractional parts: $= {12} + {\dfrac{33}{18}} - {8} - {\dfrac{16}{18}}$ Bring the whole numbers together and the fractions together: $= {12} - {8} + {\dfrac{33}{18}} - {\dfrac{16}{18}}$ Subtract the whole numbers: $=4 + {\dfrac{33}{18}} - {\dfrac{16}{18}}$ Subtract the fractions: $= 4+\dfrac{17}{18}$ Combine the whole and fractional parts into a mixed number: $= 4\dfrac{17}{18}$